Page 113 - DCAP304_DCAP515_SOFTWARE_PROJECT_MANAGEMENT

Unit 5: Project Approach

The waterfall model’s original objectives were to make small, manageable, individual Notes
development steps (the phases) and to provide enough control to prevent runaway projects.
There are a few problems that have caused dissatisfaction with this phased life-cycle approach.
 The new software system becomes useful only when it is totally finished, which may
create problems for cash flow and conflict with organizational (financial) objectives or
constraints. Too much money may be tied up during the time the software is developed.
 Neither user nor management can see how good or bad the system is until it comes in. The
users may not have a chance to get used to the system gradually.
 Changes that “aren’t supposed to happen”, are not viewed kindly, neither for requirements
nor during the operational life of the system. This can shorten the software’s useful life.

Because of these shortcomings, other process models have appeared. They are based on the
concept of iteration and evolution. Despite these limitations, the waterfall model is the most
widely used process model. It is well suited for routine types of projects where the requirements
are well understood.

!
Caution If the developing organization is quite familiar with the problem domain and the
requirements for the software are quite clear, the waterfall model works well.

5.3.2 V-Process Model

The V-Process Model is an improved version of the classic waterfall model whereby each level
of the development life cycle is verified before moving on to the next level. With this model,
testing explicitly starts at the especially beginning, i.e. once the requirements are written. Here,
by testing we mean verification by means of reviews and inspections, i.e. static testing. This
helps in recognizing errors very early in the life cycle and reducing potential future defects
appearing in the code later in the life cycle.

Figure 5.2: V-Process Model

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